On-Going Reliability Testing (ORT)

On-Going Reliability Testing (ORT)

DEFINITION

An On-Going Reliability Test (ORT) is used to help derive a reliability figure through testing. An ORT can also point out weaknesses and failure modes that occur over time.

An ORT is very similar to the Reliability Demonstration Test (RDT) except that the RDT is usually performed once just prior to release of the product, whereas the ORT is an on-going test rotating in samples from the manufacturing line.

SITUATION

Since an RDT is only performed once, it cannot pick up changes that occur in the reliability of a product either due to design changes or process changes. An ORT is geared toward this type of scenario.

OBJECTIVE

We will answer your question: “How do I test for reliability”. During the product launch, an On-Going Reliability Test (ORT) is set up and units are cycled through from the manufacturing line to help monitor the projected life of the product on a continual basis and to possibly identify weaknesses.

VALUE TO YOUR ORGANIZATION

Understanding the reliability of a product during the manufacturing process is as important as during the design process.

RELIABILITY INTEGRATION

An example of Reliability Integration during ORT is as follows:

How to use the results of a Reliability Prediction in planning an ORT

Although the prediction may not be able to give an exact MTBF number, it will give a number close enough to help determine an ORT sample size and acceleration factor necessary to provide the necessary data on-going.

METHODOLOGY

An ORT consists of a Planning stage and a Testing and Continual Monitoring stage. The inputs from the customer are the number of units allocated to the test, the duration that each set of units will be in the test before being cycled through, and the stress factors to be applied (often times, these parameters are derived from analyses/detailed discussions between Ops A La Carte and the customer).

Planning Stage

In the Planning stage, a reliability goal is established. Then, an ORT model is picked (model which helps determine the total amount of time necessary to run along with total allowable failures). Then, the acceleration factor parameters, the number of units, and confidence levels are decided upon. All of this information is then used to develop a detailed test plan.

Testing and Continual Monitoring Stage

In the Testing and Continual Monitoring stage, the ORT is run and continually monitored to determine if the reliability numbers are meeting the specs. Analysis of each failure shall be performed, corrective action shall be taken if necessary, and units with the fixes shall be immediately fed back into the ORT process.

CASE STUDIES/OPTIONS

A Semiconductor Manufacturing Equipment company wanted us to write ORT plan for one of their power supplies, determining total amount of time necessary to run, the acceleration factor parameters, the number of units, and confidence levels.

ORT Plan and Monitoring Results

A Medical Device company had us write an ORT plan and then monitor results throughout the ORT process, comparing results to goals, and making recommendations on changes needed in the product.

Complete Turn-Key Solution for ORT

A small Networking company treated the ORT as a turn-key process, where we wrote the plan, tested the samples, made recommendations during test, and wrote on-going reports.